The effects of(NH4)2SO4 concentration(c((NH4)2SO4))on hydrogen evolution and Mn electrodeposition on stainless steel(SS)in different potential ranges were investigated by linear sweep voltammetry(LSV),electrochemical ...The effects of(NH4)2SO4 concentration(c((NH4)2SO4))on hydrogen evolution and Mn electrodeposition on stainless steel(SS)in different potential ranges were investigated by linear sweep voltammetry(LSV),electrochemical impedance spectroscopy(EIS),potentiostatic polarization,chronoamperometry,scanning electron microscope(SEM)and X-ray diffraction(XRD)techniques.The results show that the NH4^+discharge reaction(NDR)intensifies the overall hydrogen evolution kinetics,and the NDR is catalyzed by increasing c((NH4)2SO4)and over-potential.The electro-crystallization of Mn on SS follows a three-dimensional progressive nucleation and diffusion-limited growth mechanism.Increasing the over-potential could accelerate the nucleation rate and also cause the decline of the nucleation density.The absorbed Mn^2+preferably discharges at low over-potential.Increasing c((NH4)2SO4)at medium over-potential could improve the current efficiency and produce more block-like grains.The nucleation process is suppressed by increasing c((NH4)2SO4)at high over-potential,at which the formation of columnar grains with higher hydrogen contents becomes prevailing.展开更多
Influence mechanism of sulfide ions(S^2-) during manganese electrodeposition from sulphate electrolyte was investigated. Under the experimental conditions, S^2- ion concentration and electrolyte pH represented signifi...Influence mechanism of sulfide ions(S^2-) during manganese electrodeposition from sulphate electrolyte was investigated. Under the experimental conditions, S^2- ion concentration and electrolyte pH represented significant multiple effects on the cathode current efficiency. Scanning electron microscope(SEM) indicated that electrodeposition manganese layer(EML) became refinement as S^2- ion concentration was increased. X-ray Diffraction(XRD) displayed that S^2- ion had negligible influence on the preferred orientation of the crystalline layer of the EML. S^2- ion had no influence on the chemical composition of EML. S^2- ion could improve the corrosion resistance of EML. The interaction mechanism of S^2- ion with manganese electrodeposition was systematically explored by analysing E-pH diagram, cyclic voltammetry curve, cathode polarization curve and electrochemical impedance method.展开更多
基金Project(1053320170703) supported by the Fundamental Research Funds for the Central Universities of Central South University,China
文摘The effects of(NH4)2SO4 concentration(c((NH4)2SO4))on hydrogen evolution and Mn electrodeposition on stainless steel(SS)in different potential ranges were investigated by linear sweep voltammetry(LSV),electrochemical impedance spectroscopy(EIS),potentiostatic polarization,chronoamperometry,scanning electron microscope(SEM)and X-ray diffraction(XRD)techniques.The results show that the NH4^+discharge reaction(NDR)intensifies the overall hydrogen evolution kinetics,and the NDR is catalyzed by increasing c((NH4)2SO4)and over-potential.The electro-crystallization of Mn on SS follows a three-dimensional progressive nucleation and diffusion-limited growth mechanism.Increasing the over-potential could accelerate the nucleation rate and also cause the decline of the nucleation density.The absorbed Mn^2+preferably discharges at low over-potential.Increasing c((NH4)2SO4)at medium over-potential could improve the current efficiency and produce more block-like grains.The nucleation process is suppressed by increasing c((NH4)2SO4)at high over-potential,at which the formation of columnar grains with higher hydrogen contents becomes prevailing.
基金Funded partly by the National Natural Science Foundation of China(No.21376273)the National Science and Technology Support Program of China(No.2015BAB17B01)the Open Research Fund of Hunan Provincial Science and the Technology Plan Project(No.MN2017K05),China
文摘Influence mechanism of sulfide ions(S^2-) during manganese electrodeposition from sulphate electrolyte was investigated. Under the experimental conditions, S^2- ion concentration and electrolyte pH represented significant multiple effects on the cathode current efficiency. Scanning electron microscope(SEM) indicated that electrodeposition manganese layer(EML) became refinement as S^2- ion concentration was increased. X-ray Diffraction(XRD) displayed that S^2- ion had negligible influence on the preferred orientation of the crystalline layer of the EML. S^2- ion had no influence on the chemical composition of EML. S^2- ion could improve the corrosion resistance of EML. The interaction mechanism of S^2- ion with manganese electrodeposition was systematically explored by analysing E-pH diagram, cyclic voltammetry curve, cathode polarization curve and electrochemical impedance method.
